Stressed panel double wall construction



6 Sheets-Sheet 1 n 24 /iZ2/ZZ Oct. 26, 1943. l. F. LAucKs STRESSED PANEL DOUBLE WALL CONSTRUCTION Filed Oct. 24, 1942 Oct. 26, 1943. l. F. LAucKs STRESSED PANEL DOUBLE WALL CONSTRUCTION 6 Sheets-Sheet 2 Filed Oct. 24, 1942 Oct. 26,k 1943. l. F.1 AucKs STRESSED `PANEL DOUBLE WALL CONSTRUCTION Filed 001'.. 24, 1942 6 Sheets-Sheet 43 :Eg: 4- f7 IRVING LAUC Ks Oct., 2, 1943;, l. F. I AucKs 2,332,732

STRESS'ED PANEL DOUBLE WALL CONSTRUCTION Filed oct. 24, 1942 e sheets-sheet 4 gmc/Mofa IRS/ING- E LAUcKs @6%. 26, 1943. l, F` LAUCKS v 2,332,732l

Filed oct. 24, 1942 IRVING F LAUC KS 1l WM 0cm 269 19431. 1. F. LAUCKS 2,332,732

STRESSED PANEL DOUBLE WALL CONSTRUCTION FiledfOct. 24, 1942 6 Sheets-Sheet 6 wuc/rvbov IRVING F. LAUCKSv Patented Oct.v 26, 1943 .UNITED STATI-:s

PATENT .OFFICE STBESSED PANEL DOUBLE WALL CONSTRUCTION Irving F. Laueks, seattle, wash., assignor to I. F. Laucks, Inc., Seattle, Wash., a lcorporation of Washington l i Application October 24, 1942, Serial No. 463,239

-of assemblying walls using these units, and the resulting new type of wall.

'I'he term stressed panel double wall construction" is used to describe building wallsl consisting of two surface sheathings of panel material spaced apart by attached studding to form double walls and so constructed as to provide a large area of attachment of the studding to the panels effective to transfer a substantial proportion of the stresses from the studdingto the panels while simutlaneously supporting the studding against deflection, thus forming a stiff structure similar in functionto a box girder 'or built-up column. While the invention is not limited as to the kind of paneling material, as will be subsequently described, plywood and particularly a novel kind of plywood is considered preferable as the surfacingV for 4the walls as shown and described in copending application, Serial No. 352,014 of Laucks et al., filed August 9, .1.940.

In recent years, numerous attempts to develop improvements in house construction have demonstrated the feasibility of replacing lath and plaster with panel or plywood wall sheathing. Success with the panel or plywood construction has also emphasized its adaptability for extending the use of shop prefabrication, thus affording further savings. Many proposals have been directed towards these ends, but, as is usual in a rapidly developing field, some of the proposals have proved disappointing in practice and none has gone so far as seems possible and desirable.

The present invention discloses a further advance along these lines which has successfully met the test of extensive practical experience.

In general terms, itmakes use of panel or plywood wall sheathing in the place of lath and plaster and particularly permitsextensiveshop prefabrication with elimination -of waste while providing great simplicity in erecting the house walls. The resulting walls are also stiffer, lighter, stronger and more easily decorated than previous constructions and these results are obtained with an important over-#all economy. Furthermore, another advantage is obtained'not hitherto available in prefabrication, namely, the

elimination of hampering restrictions as to the freedom' and flexibility of individual design.

-i Hitherto, freedom in h'ouse design as to such 55 (ci. en -4) matters as the length of the room Walls or the location and dimension of service openings (such as windows and doors) has only been obtainable A where wall prefabrication was eliminated and the house completely constructed on the job -in the usual way. 'Ihis restriction is believed to have been a serious obstacle standing in the way of the adoption of 'prefabricating methods and its elimination is an important advance. Other objects and advantages of the invention will be apparent from the subsequent description.

Theinvention provides double-faced, studsupported room walls having service openings as required for windows, doors and the like and formed of the novel wall units, the wall being characterized by the feature that the blank wall Y portions defined in the space extending from floor to ceiling laterally adjacent the service openings are smoothly continuous without joints or interruptions of surface, while the wall portions defined in the spacesvertically above andbelow the service openings are preferably of theA same construction as the rest of the lblank walls and of a width dimension which permits their V inclusion in a .common frame along witha service opening of any reasonable size. The new methodA thus includes installing continuous, panel faced, blankV wall units from door to ceiling in the areas between or laterally adjacent to the service openings along with opening units which includes similar panels in the wall areas l dened vertically between floor and ceiling above or below the openings. In` the case of walls which require no service openings, smoothly continuous walls are also provided. This is -all accomplished with-shop prefabricated units, either blank wall units or opening units containing any desired service opening. As will be disclosed in the subsequent descriptiomthis can be done by the method of the present invention without any hampering limitations as to the locationl or dimensions of the service openings or as to the length of room walls and this much desired flexibility is obtained. without any penalty of wasted material.

'Referring now tothe accompanying drawings: Figure 1 shows a plywood wall surfacing panel commonly known by the trade name of Big Board" and as produced in accordance with the aforementioned application Serial No. 352,014;

- Figure 2 shows a Big Board panel, the same as shown in Figure 1 lexcept that one surface is covered with a glued-on textile covering; Figure 3 show/sla typical blank wall unit constructed with plywoodlBig Board" facing panels glued or otherwise secured' to interposed supporting studs;

Figure 4 shows a typical opening unit including a window.

Figure 5 shows a jamb stud use d in making up a windowunit;

Figure 6 shows a typical opening unit including a door;

Figure 7 shows a jamb stud used in making up adoor unit;

Figures 8, 9, 10, 11 and 12 show respectively adjacent views of a blank wall unit, a door unit,

- another blank wall unit, a window unit, and another blank wall unit, all the units being dimen- 1 sioned for successive assembly to make up a .described in the aforesaid application of Laucks et al., Serial No. 352,014; l

Figure 17 is a sectional view of a wall unit showing Big Board" panels secured to the studding on opposite sides as shown in Figure 3; and

Figure 18 is an enlarged detail sectional view taken 4along one of the joints for uniting the panels of the Big Board" as illustrated in the aforesaid pending application.

Referring now to the drawings in detail, and particularly to Figures 1 and 16, the Big Board panel is identified as a whole by the reference numeral I0. The width dimension is usually about eight feet to accommodate the ordinary height of room walls and the length dimension as employed in the present invention may be variable but is usually about sixteen feet or more. In the drawings, as best shown in Figure 16, the numeral II indicates the face plies and I2 the intermediate ply. The panel is of the customary odd number of plies, usually three ply, and is of indeterminate length when speaking of the panel considered as a whole but has the unique feature that the direction of the grain of the face plies I I runs in the direction of the long dimension of the large panel as shown in Figures 1 and 16. This long dimension is indeterminate so that individual panels are readily provided cut off to a length dimension equal to'the greatest length of any room wall in an ordinary house. The

width dimension, again referring to the panel as' a whole, is as stated', preferably about eight feet to. accommodate the usualheight of room walls and it is noted that the direction of the face grain runs transverse the eight foot or height dimension.` As described in Serial No. 352,014, these Big Board panels are made up from a series of individual panels I3 of normal commercial size as produced by plywood plants having a long dimension of about eight feet and a. short dimension of about four feet but are specially made in the plywood mills with the -grain of thevouter face plies parallel with theshort dimension as contrasted with the usual practice in the plywood plants of having the grain of the face plies extend parallel with the long dimension. From these individual panels, the Big Board panels are constructed by Joining them together as at I4 along their longestmarginal edges with a joint shown best in Figure 18 which unites the terminal fibers of the face plies of one panel to the corresponding fibers of the adjacent panel, the object of this procedure being to produce a Big Board which has approximately the strength that it would have if the face plies ran continuously along the face of the board without any breaks. A preferred form of scarfedjoint is shown in Figure 18.4 The lines I4 are imaginary siLce in the actual panel or facing there is no clear line of demarcation, the grain of the several panels merging into each' other at the joint with the only suggestion of a line denoted by the change in the direction of the annular rings.

In the subsequent description, it will be noted that these Big Board panels are preferredlas the surface facing material of the double wall units shown in Figures 3 and 17. Two boards Il are securely glued at I5 to the opposite edges I6' of a series of interposed vertical studs I1 as shown in Figures 3 and 17 and in all such instances the exposed grain of the plywood runs parallel with A of houses because of its ease of decoration, while the bare board may be used for either exterior or interior wall unit facings. In the same way, in constructing the double wall unit, plywood of exterior grade glued with a highly weather-resistant adhesive may be used forthe exterior face of the double wall units while plywood glued with a water-resistant glue may be used for the internal face of walls since these faces are not exposed to weather.

Referring to Figure 3, there is shown a double wall unit faced with plywood facing layers Il spaced apart by interposed studs I1 as used in prefabricating the blank wall unit portions of the house walls constructedv according to the present invention. The Big Board facing panels lli are preferably glued to the interposed studs I1 although other suitable seeming means may be used. These facing panels are usually three-ply, commonly 1% in thickness, and a common dimension for the cross section of the studs is x 2%. The facing panels are glued to the opposed narrow edges of the studs so that the studding space is 2%" thick and the over-all thickns of the double wall unit is approximately 3%". The studs are located vertically conveniently on about twelve inch centers and are desirably glued over their entire contacting edge surfaces to `the facing panels. preferably with a water-resistant adhesive. It is preferably provided that the. studs l1 are somewhat shorter than the dimension of the facing panel which corresponds to the height of the roomwalls and are glued on to the facing panels in such-a manner that the studends are recessed back a short distance, usually about one inch, from the top and bottom edges or extremities of the facing panels as shown at I8. The object 'of this arrangement. as shown in Figure ,14 is to permit the weight of the structure Labove the studs is y also carried on the upper ends of the studs since the ceiling plate rests n the studs, while the upper edges 'of the facing panels are kept free of any structure above and hence do not carry any direct load on their edges. As shown in Figure 14, the panel has its edge 20 below the top surface of the ceiling plate as shown at 24.

It is to be noted by reference to Figures 3, 14 and 17 that the lateral faces 25 of the outermost studs are also recessed backas shown at 26, a

short distance from the lateral extreme edges 21` I of the facing panels. This is to provide blank wall units having protruding lateral panel edges 21 adapted. to enter corresponding'recesses in service units as will be explained subsequently.

From the foregoing it will be noted that integral blank Wall units generally designated by the letter U are produced of indeterminate length "consisting of the facing layers I0 connected to the studding l1, the facing layers being formed of panels as described with the grain of the external plies Il extending in the length direction of the unit and transverse to the length direction of the wall height panels. The'facings l0 are secured to the studding preferably by gluing and the studs extend parallel to the length di- V ent invention to cooperate with adjacent blank wall units as illustrated in Figures 3 and 13. Referring to the drawings, a conventional window frame assembly 28 which may be any desired type of window, such as for example the ordinary double hung window, issecured between two special marginal jamb studs 29 shown in detail in Figure which run from floor to ceiling. These jamb studs may be conveniently run out of ordinary fir stock to a width the same as the total thickness of the double wall units (in this instance, 3%f'). One of the fiat faces 30 of the jamb studs is secured to the outer edges 3l of the styles of the window frame as shown in Figure 4 as by gluing or in any suitable manner.

-The opposite edge is conveniently rabbeted at 32 to forma protruding face or tongue 33 equal in width to the studding spaces (inthis case, 2%) and to leave at the extremities two rabbeted grooves 34 having a length coexte'nsive with g the` window frame. These grooves are each dimensioned to form with the window frame reabove and below the window frame, both edges of the stud 29 are cut away entirely as at 36 so that the jamb stud Width above' and below the window frame is the same as'the depth of the wall opening and tongue 33 (in this instance. 2%) and the edge faces 31 of the jamb stud provide a flat surfaced support for the projecting vedges 21 of the wall panels to which they may be glued.

Further, referring to Figure y4, above'and below l the window frame 28 proper are located portions or double wall units U equal to the desiredblank wall space between the floor andthe bottom of the window and between the top `of the window and the ceiling. These comprise the usual facing panels Illtand studs I1 as shown in Figure 3 and are placed with their studs in the vertical position. Thus, all the elements of the window unit,

including the window assembly 28 and the blank wall sections, are secured into a common frame by means of the two marginal jamb studs 29 en closing the frame to which the window and blank wall units are secured. It is to benoted also that, as with the blank wall unit shown in Figure 3, the ends of the studs I1 and jamb studs 29 are provided recessed back about one inch from the Y top extremities of the facing panels lll as shown at 22-24 so as to free the facing panels lll from carryingvvany load on their edges.

Referring to Figures 6 and`13 there is illustrated a typical door unit made according to thev present invention. It willbe noted that this is very similar in its design to the window unit illustrated'in Figures 4 and 5. A door frame 38 which may be of any suitable designas to width and height, is enclosed between two jamb studs 39 which run from floor to ceiling. These are identical in section With-the jamb studs 29 illustrated in Figure 5 and perform thevsame functions of enclosing the frame 38, of providing grooves 40 for engagement of the projecting panel edges 21, of adjacent cooperating double wall units U, and of securing tothe assembly a blank wall unit section U dimensioned to fill the space between the top of the door and the ceiling as shown in Figure 6. Also, as in the window units, the jamb studs 39 andthe studs I1 of the blank wall unit are arranged to be recessed back about one inch at the floor and ceiling lines respectively to engage the horizontal oor and ,respectively and successively a blank wall unit, a

door unit, another blank wall unit, a window unit and a third blank Wall unit. These are shown in successive location in the drawings to illustrate their cooperation in constructing a typical room wall as shown in Figure-13. As previously described, rabbeted grooves 34-49 provided on the jamb studs 39 of the door unit shown in Figure 6 and the window unit shown in Figure 4 provide engagement for the laterally projectingedges 21 of the wall panels Ill on the blank wall units U. In Figure 13, the same units are shown assembled in place to provide a complete room wall having one window and one door. f

The van illustrated in Figure 13 and compr'ising two openings, namely, the window 28 and door 38 is smooth and continuous since the projecting margins 21 of the panels have a register` ing fit within the recesses 35 and 40' provided by the respective jamb studs, and the wall units above and below the window 28 and above the door 38 are so constructed that the facing layers l terminate short of the thickness of the jamb studs as illustrated at 4I in Figures 4, 6, 9 and ll whereby the projecting edges 21 of the wall units engage over the exposed edge portions of the jamb studs and abut the terminal edges 21 of the units above and below the wall openings.

In Figure 14 there is illustrated the preferred arrangement of the ends of the normal studs I1 and, in Figures 4 and 6, i. e., in the case of an opening unit, of the jamb studs 29 and 39 whereby the top and bottom extremities of the facing panels I0 are permitted to ystraddle the floor plate 2 I-at the bottom of the wall and the ceiling plate 23 at the top of the wall. It is noted that the oor plate 2| and the ceiling plate 23 are thicker than 'the amount which the ends of the` ture is carried directly on the edges of the facingV panels of the units. What weight is carried by the facing panels is directly supported by`the studs and since each unit consists of facing panels I0 securely glued to the studs I1 or the studs 2li-39, the stresses applied are transmitted through the studs which act as stress distributors. This arrangement frees the facing panels from an'y concentration of stress-such as would be likely to cause them'to warp or buckle.

In Figure l5, there is illustrated thel operation of the tongue and groove arrangement for interlocking blank wall units U illustrated by Figures 14 'and 17 in cooperation with adjacent opening units as illustrated in Figure 4 or 6. The interlocking action shown in Figure 15 is a view of a section taken horizontally parallel to the :door

line through contacting sections of a blank wall unit and adjacent window or door frame. 'I'he numeral I0 indicates the facing panels of the blank wall unit and the numeral I'I indicates one of its lateral supporting studs. It is noted that the stud I1 isrecessed back from the projecting ends of the facing panels and these proj ecting ends 21 enter rabbeted grooves 34-40 in the face of either the jamb stud 29 which is attached to the adjacent parts of the window frame 28 or jamb stud 39 associated with the door frame 38 as the case may be. This arrangementpermits a convenient method of assembly with an interlocking engagement between, the adjacent units. If desired in assembling the units, the engaged portions may be supplied with glue, or they may be nailed together, or in some instances they may be left unattached to each other if it is desired to make the wall demountable at some subsequent'date.

Important advantages of the invention are found in connection with the prefabrication of the walls of dwelling houses and similar structures. The method of operation may be exemplified as follows: Materials are assembled in the about eight feet) and another dimension equivalent to the greatest wall length of a fairly long room (for example, sixteen feet). The paneling material maybe of the usual thickness for wall covering, conveniently about inch. Preferably,

one piece plywood panels of these dimensions are obtained, although other materials, such as various types of composition wall boards, may also be used in some instances. AIn the case of plywood, the usual three-ply material of wall board grade may be used and this material may be provided with the direction of the wood grain in the faces running either approximately parallel with the eight foot' dimension of the large panels or transverse the eight foot dimension-of the component panels.' However, for best results, it is highly desirable to use plywood wall board having face grain running transverse the eight foot dimension so that when the panels, after attachment to their supporting studding, are erect as covers for walls of eight foot height, the face grain of the outer plies will run parallel to the direction of the floor and ceiling lines and transverse the direction of the vertical supporting studs. Largepanels of this type, now known in the trade as Big Board, are commercially available, their method of manufacture and properties being described in detail in the aforementioned copending application, Serial No. 352,014.

Having provided, for example, a supply 0f Big Board" panels which may be conveniently' 8' x 16' x 1%", a supply of special studding is also prepared. Thisstock may be run from ordinary fir lumber and is desirably cut .to a rectangular cross section of X25/8" and is conveniently suppliedV in one standard length cut about two inches'shorter than eight feet. From these ma.

` terials, a large supply of integral blank wall units, as illustrated in Figure 3, are fabricated, using the Big Board faces I0 in the full sixteen foot length and supplying interposed vertical studding I1 which may be conveniently located on about twelve inch centers. For best results, it is desirable to use a water-resistant glue and glue the entire edge of the studstothe face panels. i 1

A convenient method of fabricating these assemblies is to glue themupin a hot press. As indicated in Figure 3, the studs are about two inches short of the eight foot dimension of the panels and they are located symmetrically between the panel faces so that their ends are recessed back from the top and bottom edges of the panels about one inch. 'I'he resulting prefabricated'panel faced double wall units U according to the method of the presentinvention, constitute the raw material or stock units from which all the blank wallportions of the house walls are constructed.

For specific house jobs, as they come in, these large stock blank wall units are cut up into longitudinal sections of the same area as the vertical portions lof walls, or entire room walls, which are free from service openings. In the case of the portions of walls which have service openings, the sections of these blank wall units are cut to fit the spaces from the corners of the room to the nearest lateral edge of any service opening .and also lto fit the spaces between the lateral edges of two 'service openings. Smaller portions of these blank wall units may also be cut to ll the areas of blank walls vertically above doors and vertically above and below windows. Thus wall height sections of blank wall units are provided for all the blank wall areas of the house.

The wall opening units are made up as follows: the small blank wallI sectionsrequired to ll out the blank wall spaces above doors and above and below windows are fabricated into a frame along with the window or door, as the case may be, by means of special marginal jamb' studs as illustrated in Figure 4 for a window unit and Figure 6 for adoor unit. y

As previously described, it will be noted that all of the wall height blank wall units are cut from the stock units in such a manner that a lateral i. e., an edge stud is not allowed to come out flush with the lateral panel' edges. This -mere1y calls for the exercise of a little'care in cutting so that all blank wall units are cut out with the lateral edges of their facing panels' projecting at least one inch beyond the lateral face of-.the nearest stud; These projecting edges in the blank wall units consequently become available to function as tongues adapted to cooperate with corresponding grooves cut in the lateral faces of the jamb studs of the window and door.

units as above described. y It is noted that the marginal jamb studs alongthe side edges of the window or door, as the case may be, are'provided with rabbeted -grooves dimensionedto receive the projecting panel edges of the adjacent blank wall units. It will be noted also, however, that this groove only extends along the vertical height of the actual door or window frame while the portion of the jamb stud which projects above a door (or in th'e case of a window, whichI projects above and below the window) is machined off" across the whole face to the full depth of the groove. Inv constructing the opening units, the previouslymentioned small sections of blank wall units which are preferably cutl to Aiill the area of the opening are fitted in their proper positions with their included supporting studs in vertical position and secured in. place with their panel edges overlappingabout half-way on the edg'ev of each of the two marginal jamb studs.

The lateral edges of the blank wall units and openingv units are thus arranged/cooperatively so that when a blank wall unit is brought up into vposition adjacent to an opening unit, its panel edges fit into the rabbeted grooves along the sides of the window or door casing and abut the corresponding lateral edges of the small blank wall sections above the door and above and below the window, this abutment coming on the face of thel routed-Dif portion ofthe jamb studs.

With thes'e arrangements, it'will be seen that it is a very simple matter upon receiving an order for house walls to prepare from the stock blankgwall units and from conventional door and window frames a series of blank wall units and a cooperating series of opening units so that complete walls with the desired openings are provided and the openings are located exactly according to the preference of the builder or architect. The locations and dimensions Qfnthewopen# ings present no problemsl and it is equally' convenient and economical to make up the necessary units regardless of the chosen location. Extensive experience with this new method of prefabrication has shown that it is remarkably economical as to both labor and material. The

cutting waste, for example, is readily held below two per cent.

It will be noted that the principles of this invention, so far as the fabrication of desired walls is concerned, will work well with any preferred form of surface paneling regardless of whether it is, for example, artificial composition board of any type that lcan be readily cut and glued to studding or whether it is plywood with the face grain running either vertically or horizontally. In any case, the glued-up double wall units have-many of the desirable characteristics of a box girder since an adhesive union is provided between'the paneling and the entire exposed surface of the s tud edges so that the panels constitute a diagonal bracing effect to the studding and absorb stresses received therefrom. As has previously been recognized, this provides a wall of considerably greater stiffness than if the panels were merely nailed to the studs. This additional stiffness is largely due to the glued' By controlling the grain direction of the fibers of the outer plies of the plywood further advantages can be gained. If plywood is used for the wall surfacing and the grainof the face plies runs parallel to the eight foot dimension (i. e., vertically up and down the face of the wall as has been the practice hitherto in the use of plywood wall board in house construction) a fairly strong wall is produced, but it is noted that the wall is not particularly stiff against pressure in the unsupported spaces between two studs. The panels are easily deflected inward by pressure so that adequate stiffness in that case is either not obtained or velse requires thicker plywood or greater area of stud support than is required when the preferred method of the present invention is employed. Thus, if the Big Board described in S. N. 352,014, is ,used for the wall sur- `facing, the direction of the face grain is reversed so that the grain of all the face plies runs transverse the studs. In this instance, a great gain in strength and stiffness is obtained without the provision of any added material. With this oonstruction, the tensile strength of the face grain fibers running transverse the studs offers a strong resistance to inward or outward deflection of the walls between the stud locations. Thestiifness and strength of such a wall becomes fully adequate to give equal satisfaction in that respect as compared to lath and plaster walls. Due to this important gain, it is of course very desirable in practicing the present invention to sur- `yface the wall units with the Big Boards described in S. N. 352,014.

. The present invention is a radically new departture in the field of prefabrication. Comparison with existing methods reveals important advantages. Hitherto, most prefabrication has been done by one of two methods. In one method,

`which may be defined as the modulus system,

able expense become necessary since a single unit only covers for example four feet of wall. Also, ield joints occurring every four feet require some sort of covering or concealment, and, with the joints so numerous, it is impractical to provide walls and the location and width of all openings must conform exactly to the modulus dimension. Thus, the modulus system requires an excessive number of field joints and imposes rigid dimensional restrictions on house design. The nmerous joints between the units also tend to weaken the wall and the complete supportingl frame needed for each unit adds objectionable weight and consumes unnecessary material.,

Another system of prefabrication, which may be called the cut-out system, consists of providing either on the job or in the shop the framing for an entire wall, including framing around the desired openings, and then covering the framing with single large surfacing panels from which the areas of any service openings are cut out either before or after erecting. This system, of course, involves serious waste of surfacing board lost by cutting out the openings, and it fails to provide the desirable extensive use of prefabri- -f cation available in the system of the present invention. A

Thus, it will be noted that the method of the present invention has outstanding advantages over both of these other systems. Asl compared to the modulus system, the present -invention greatly reduces the number of eld joints. Many walls have no joints at all, and'where there are windows or doors, fewer joints are required than facings of. structurally strong material of sub' stantially similar properties with respect to contraction and expansion and the Spaces between studs extending from oor to ceiling and having its blank wall area above a door or above and below a window and detlned by said jamb studs filled by prefabricated units each comprising a pair of substantially parallel panels secured to and spacedapart by at least two studs, the l studs terminating short ofthe top and bottom edges of the panels, the 'panels being thin facings of structurally strong material of substantially similar properties with respect to contraction and. expansion and the spaces between the studs being open at both ends and gfrom end to lleast one opening containing wall unit as described in claim 3 vand at least one blank wall unit comprising a pair of substantially parallel panels of wall height secured to and spaced apart by at least two studs, the studs terminating short of the top and bottom edges of the panels, the panels being thin facings of structurally strong material of substantially similar properties with respect to contraction and expansion and the spaces between the studs being open at both ends and from end to end, all of said studs being disposed inwardly with respect to the lateral edges of the panels soas to provide longitudinal recesses between said lateral edges, the jamb studs of the opening containing unit being each provided with an outwardly projecting tongue portion running from oor to ceiling, said tongue portions having-a widthequal to that of the longitudinal recesses between the lateral edges of the blankwall units, at least one of said tongue portions being received in the longitudinal recess of an adjacent blank wall unit with the said lateral edges ofthe blank wall unit dening said recess attached to the adjacent edges of the jamb stud.

the studs being open at both ends and from endx to end, all of said studs being 'disposed inwardly with respect to the lateral edges of the panels so as to provide longitudinal recesses between said lateral edges.

2. A prefabricated wall unit comprising a pair of substantially parallel panels at least one of which is made of plywood, said panels being of wall .height secured to and spaced apart by at least two wooden studs, the studs terminating short of the top and bottom edges of the panels, the Vpanels being thin facings of structurally strong material of substantially similar properlties with respect to contraction and expansion and the spaces between the studs being open at both ends and from end to end, all of said studs j being disposed AVinwardly with -respectvtosthe latof the door or window frame, Asaid unit being laterally enclosed between two marginal .lamb

5. The method of constructing a room wall from prefabricated units comprising constructing at least one opening containing wall unit as described in-claim 3 and at least one blank wall unit comprising a'pair of substantially parallel panels of wall height secured to and spaced apart by at least two studs, the studs terminating short of the top and bottom edges of the panels, the panels being thin facings of structurally strong material of substantially similar properties with respect to contraction and expansion and the spacesbetween the studs being open at both ends and from end to end, all of said studs being disposed inwardly with respect to the lateral edges of the panels so as to provide longitudinal o lrecesses between said lateral. edges, forming the jamb studs of the opening containing wall unit with outwardly projecting tongue portions runportion into the longitudinal recess between the vertical distance between a iloor and ceiling and a lateral distance substantially equal to the width lateral edges of an adjacent'blank wall unit and attaching said lateral edges to the adjacent edges-A 'from prefabricated units comprising constructing at least one opening containing wall unit as described in claim 3 and at least one blank wall unit comprising a pair of substantiallv parallel assavsz panels of wall height secured to and spaced apart by at least two studs, the studs terminating short of the top and bottom edges of the panels, the

panels being thin facingsY of structurally strong material of substantially similar properties with respect to contraction and expansion and the spaces between the studs being open at both ends and from end to end, all of said studs being disposed inwardly with respect to the lateral edges of the panels so' as to provide longitudinal 10 recesses between said lateral edges,'forming the jamb studs of the opening containing wall unit with outwardly projecting tongue portions running from oor'to ceiling, connecting said units into a wall by inserting at least one tongue portion 'into' the longitudinal recess between the lateral edges Aof an adjacent blank Wall unit and attaching said lateral edges to the adjacent edges of the tongue portion, and inserting floor and ceiling plates in the. recesses of the top and bottom edges of the units so that the plates engage the studs for supporting the units, said last mentioned recesses being formed by-having the studs terminate short of the top and bottom edges of the panels of the units.

IRV'ING F. LAUCKS. 

